Field of the Invention
This invention relates to the recovery of potable water from ambient air. It is specifically directed to a machine adapted to recover and purify water contained in ambient air.
Background Art: U.S. Pat. Nos. 5,669,221 and 5,845,504, the disclosures of which are incorporated by reference, describe portable water dispensing machines capable of recovering liquid water from the humidity of ambient air. These machines are constructed and arranged to draw in moisture-laden air from the surroundings, and to cool the resulting stream of air to below its dew point, thereby recovering liquid water. The recovered water is then sanitized for human use. The sanitization process may involve UV radiation treatment and various forms of filtration.
Various other apparatus constructed and arranged for extracting potable water from moisture laden air are described in U.S. Pat. Nos. 4,351,651; 5,106,512; 5,149,446; 5,259,203; 5,301,516; 5,398,517; 5,517,829 and 5,701,749. The ""651 patent, to Courneya, discloses a water generator using a heat sink positioned below the surface of a body of water or earth. The temperature at a condensation surface achievable with this arrangement necessarily limits the operating range of the device and water output. Furthermore, this device cannot be easily transported for use indoors. No provision for bacterial control is made.
The ""512 patent, to Reidy, teaches a portable water generator with provisions to fill a single removable internal water container, or to manually divert water production to an external container for storage. Reidy""s device uses a fan to pass filtered air from an entry port located at the device""s front, through a dehumidifier, and to an exit port located at the device""s rear. Recovered water is treated with UV radiation and filtration. No provision is made to control the temperature of the stored water. The ""446 patent, also issued to Reidy, teaches a similar apparatus, but lacking provisions for subsequent treatment of collected water. An illustrated device has an air ducting arrangement to provide outside air to a device operating indoors.
The ""203 patent, to Engel et al., discloses a compact device to extract water from air using a refrigeration system. Provisions may be made to provide dispensable warm or cool water. The refrigeration system used to condense water from the air is also used to heat or cool the stored water. Collected water is filtered, but not additionally treated.
The ""516 patent, to Poindexter, teaches a device to extract water from air. This device uses refrigerated cooling coils to condense water from air ducted through a cabinet. Collected water passes under influence of gravity from a collection pan to a single collection container through a filter. No further treatment of the collected water is disclosed. The device is designed for easy access to clean condenser coils and associated structure. No provision is made for dispensing water at temperatures above or below ambient. The ""517 patent, also to Poindexter, is a continuation of the application which issued as the ""516 patent. This subsequent patent discloses a cleaning apparatus to clean a coil and collection pan in a water extracting device.
The ""829 patent, to Michael, discloses a water generating device using either a refrigerated or thermoelectric water condenser. Generated water is filtered and treated with a disinfectant prior to storage in a container. The water is again filtered to remove bacterial residue, viruses, germs and the like, as well as residual disinfectant, when pumped from the storage container to a dispensing tap.
The ""749 patent, to Zakryk, teaches a water generator apparatus using a refrigerated fin and tube condensing unit. Water condensed on the condensing unit flows by gravity directly into a collection reservoir. Water stored in the collection reservoir is filtered and may be exposed to UV radiation prior to being dispensed through a delivery coil of conduit and then to a spigot. As long as sufficient water is present in the apparatus, a quantity of filtered water remains in the delivery coil at all times, ready for immediate dispensing. The delivery coil, and water contained therein, are cooled by submersion in the collection reservoir. Water in the delivery coil is prevented from stagnating by periodic cycling of a valve to permit water flow through a return loop to the collection reservoir.
The above discussed water generator devices are perhaps adequate for their intended purposes. However, improvements in ease of use, reduction in cost, optimizing process parameters including air flow and condensation, preventing overflow, and maintaining the quality of recovered water are still desired.
The present invention comprises an improved water generator constructed and arranged in a fashion generally similar to that disclosed by the ""221 and ""504 patents, but adapted to avoid some the inconveniences and costs associated with the construction and operation of those and other previous designs. Of particular significance, water is pumped from a collection pump through an aerator into a holding tank. Collected water may be treated with ultraviolet (UV) radiation to destroy pathogens prior to storage in the holding tank. In a preferred embodiment, water in the holding tank is intermittently circulated through an aerator. Upon demand, water is drawn from the holding tank to either of secondary cold water or hot water tanks. This demand stream is drawn through a filtering system. Preferred embodiments make use of a spiral condensation coil to improve condensation collection. It is generally preferred to utilize an electric probe for chilling, although FREON and cold plate chilling systems are operable. Chilled water may be circulated through an auxiliary condensation system, whereby to increase the rate of water recovery.
In general, an embodiment of the invention includes a cabinet enclosure having a volume defined by a front, a rear, and first and second sides. A fluid collection system and a fluid dispensing system are at least substantially contained within the cabinet. Preferred embodiments are arranged for intake of ambient air through the first side, then through a dehumidifier, then exhausted through the second side. Such an arrangement allows the invention to be stored near a wall without impeding the air flow.
While any commercially available dehumidifier is operable, it is preferred to use a dehumidifier having a first water condensation surface arranged in a substantially circular coil. Such a configuration generally maximizes a water condensation surface area and tends to drip recovered water into a more centralized location for convenient collection. It is further preferred to orient the coil to have its effective diameter oriented substantially vertical and perpendicular to the direction of air flow through the coil. In certain embodiments, the dehumidifier may also include a second water condensing surface which is cooled by circulation of chilled recovered water. The second surface may be arranged either upstream or downstream of the first surface with respect to the air flow across the surfaces.
The fluid collection system typically includes a dehumidifier, a pump reservoir, and a holding tank to receive recovered water. The pump reservoir is generally located below a condensation collecting coil of the dehumidifier for gravity assisted collection of recovered water. A collection pump moves recovered water from the pump reservoir to the holding tank through a first fluid path. A collection control apparatus cycles the collection pump on and off based, in part, on the water level in the pump reservoir. The collection pump is prevented from running if too little water is present in the pump reservoir. When water in the pump reservoir is at an operating high level, the collection pump is turned on, unless the holding tank is sufficiently full. The collection control apparatus also cycles the dehumidifier. The dehumidifier is turned off when the water in the holding tank is at a sufficiently high level. The dehumidifier is turned on when the holding tank is below the operating high point. A pump reservoir level safety control apparatus, such as a low cost float safety switch for automatic shutoff of the dehumidifier may be included as part of the collection control apparatus. Such a safety switch operates to prevent overflow of the pump reservoir in event of failure of the collection pump, electricity failure, clogging of the filtration system, or for other causes preventing normal operational water flow.
It is currently preferred that a bacterial treatment apparatus and an aerator apparatus are disposed in the first fluid path. A desirable bacterial treatment apparatus may be a UV light source, or an bacterially effective filter. Provisions for intermittent recycling of the water from the holding tank through an aerator may be made to avoid its stagnation. The water is also intermittently recycled through the bacterial treatment apparatus in certain preferred embodiments. A preferred recycling loop also encompasses water held within the pump reservoir. It is within contemplation to include a chemical based algae prevention system to treat water in the holding tank, such as a chlorine drip.
The fluid dispensing system typically includes one or both of a cold water tank adapted to chill and store water contained therein below ambient temperature, and a hot water tank adapted to heat and store water contained therein above ambient temperature. The dispensing system also includes a demand pump and a demand control apparatus. The demand pump moves water from the holding tank through a filtration system to the hot or cold water tanks. The demand control apparatus operates the demand pump in response to a withdrawal of water from the hot or cold water tanks. The hot or cold water tanks are typically adapted to dispense water by gravity feed through spigots. The spigots typically are carried on the front of the enclosure at a convenient elevation for dispensing fluids.